JPH09136970A - Molded synthetic resin product and crate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a molded synthetic resin product which can resist cracking even when force exerts on it by mixing two synthetic resins each of which has a specified elongation and a specified modulus with a third synthetic resin and an inorganic filler and molding the obtained mixture and to obtain a crate using the same. SOLUTION: The front cover 3F, the side cover 3G and the fan guard 3A which are produced by injection molding is obtained by molding a mixture comprising 30-50wt.% first synthetic resin (e.g. polypropylene) having an elongation of 300% or above and a bending modulus of 1,500-2,000MPa, 30-50wt.% second synthetic resin (e.g. polypropylene) having an elongation of 30% or below and a modulus of 2,000-2,4000MPa, 1-20wt.% third synthetic resin being at least one member selected from among rubbers, elastomers and polyethylenes 10-30wt.% inorganic filler (e.g. talc and calcium carbonate). An air conditioner 1 is composed of an indoor unit (crate) 2 and an outdoor unit (crate) 3. The reception and sending of signals between the indoor and outdoor control units is performed through a cable 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin molded product obtained by mixing and molding a plurality of synthetic resins, and a housing using the molded product.

[0002]

2. Description of the Related Art An example of a housing used in an air conditioner is disclosed in Japanese Patent Publication No. 7-24343. Such a housing is formed of synthetic resin, for example. Further, such a synthetic resin molded article is molded by a method generally called injection molding (injection molding).

[0003]

The above-mentioned synthetic resin molded article is, for example, a synthetic resin (e.g. polypropylene) having an elongation of 300% or more and a flexural modulus of 1500 to 2000 MPa, talc or calcium carbonate. A resin molded product was molded by mixing with an inorganic filler such as. Such a synthetic resin molded product is formed by a molding method called injection molding in order to obtain a required shape. When molded by such a method,
When the synthetic resin is injected into the mold, there will always be a part where the two flows of the divided molten material (synthetic resin material) join. This part is generally called a weld. In this weld part, the synthetic resins stick to each other in a slightly cold state, so the strength is weaker than other parts, and the weld part has a weaker force than the force applied to other parts. However, even if the sound was added, there was a drawback that it often cracked with a snapping sound. Especially in winter, when the temperature is low and the synthetic resin is difficult to deform, the synthetic resin molded product is easily cracked.

The present invention provides a synthetic resin molded product which is resistant to cracking even when a force is applied, and a housing using this molded product.

[0005]

In order to solve the above-mentioned problems, the invention according to claim 1 has an elongation percentage of 300% or more and a bending elastic modulus of 1500 to 2000 MPa.
A synthetic resin, a second synthetic resin having an elongation of 30% or less and a bending elastic modulus of 2000 to 2400 MPa, and rubber;
At least one third synthetic resin selected from elastomer and polyethylene is mixed with an inorganic filler to form a synthetic resin molded product.

According to a second aspect of the present invention, the first synthetic resin is 30 to 50% by weight and the second synthetic resin is 30 to 50% by weight.
%, The third synthetic resin is 1 to 20% by weight, and the inorganic filler is 10 to 30% by weight, and the synthetic resin and the inorganic filler are mixed to form a synthetic resin molded product. It is a thing.

According to a third aspect of the present invention, injection molding is performed using a synthetic resin obtained by mixing the first synthetic resin according to the second aspect, the second synthetic resin, the third synthetic resin, and an inorganic filler. To form a synthetic resin molded article.

According to a fourth aspect of the present invention, the synthetic resin molded article according to the third aspect is used in a housing.

[0009]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an external view of the air conditioner 1, and shows the front sides of both units, and is different from the actual installation. The air conditioner 1 is mainly composed of an indoor unit (housing) 2 and an outdoor unit (housing) 3, both of which have a refrigerant pipe (inter-unit piping) 4 and a hot water pipe (inter-unit piping).
5 and an inter-unit cable 6 are connected.
It should be noted that signals can be exchanged between the indoor and outdoor control devices via the inter-unit cable.

Reference numeral 7 is a wireless remote controller, 2A is a power plug, 2B is a flap for changing the blowing direction, and 2 is a flap.
C is a drain hose, 2D is a suction grille, 2E is a display unit, and is provided with a receiving unit for receiving a signal from an operation lamp or a remote controller. 3A is a fan guard, 3B is a combustion gas exhaust port, and 3C is an intake port. 3F is a front cover, 3G is a side bar, and these covers 3F, 3G and the fan guard 3A are the synthetic resin moldings described in the claims, and are formed by injection molding (injection molding). The cover 3F, 3G, the fan guard 3A, etc. constitute the housing 3. 3H is a sky cover.

The synthetic resin molded products 3F, 3G, 3A are
It is molded from a first synthetic resin, a second synthetic resin, a third synthetic resin, and a synthetic resin mixed with an inorganic filler. As the first synthetic resin, a synthetic resin having an elongation rate of 300% or more and a flexural modulus of 1500 to 2000 MPa (megapascal), for example, polypropylene resin is used.

The second synthetic resin has an elongation rate of 30% or less (including an elongation rate of 0%, but the elongation rate of 0% has not been found so far), and the flexural modulus is 2000.
A synthetic resin of up to 2400 MPa, for example, polypropylene resin is used.

The third synthetic resin is at least one of rubber, elastomer and polyethylene.

As the inorganic filler, for example, talc and calcium carbonate are used.

The first synthetic resin is 40% by weight, the second synthetic resin is 40% by weight, and the third synthetic resin is 10% by weight.
And an inorganic filler at a ratio of 10% by weight.

The synthetic resin molded article of the present invention molded from the synthetic resin mixed in such a ratio is a conventional synthetic resin molded article (the first synthetic resin is 75% by weight, the inorganic filler is 25% by weight).
(% By weight, see Table 1)
I experimented. In this experiment, a synthetic resin molded product as a sample was
The width was about 150 mm, the distance between the two supporting points A1 and A2 was 100 mm, and a force such as a weight was applied to the central portion so as to gradually increase, and the amount of deflection until the sample cracked was measured (FIG. 4). reference). FIG. 3 shows the measurement results. Table 1 shows the proportion of each synthetic resin and the like.
This synthetic resin molded product, both the conventional one and the one according to the present invention, are injection-molded (injection-molded) with the same mold, and both welds are formed.

[0017]

[Table 1]

As can be seen from FIG. 3, the strength is not so strong (18.0 Kg in the case of the present invention compared to 16.3 Kg in the conventional case), but the amount of deflection is about four times (conventional case). The one of this plan is 1 mm against the one of 4.1 mm
It becomes 5.0 mm), and it can be seen that it does not crack even if the present invention is bent a little.

A housing 3 made of such a synthetic resin
May have to be curved, especially during the assembly process. For example, when the fan guard 3A must be inserted into the opening of the front cover 3F (see FIG. 2). In such a case, the conventional one is very fragile when bent. Especially,
The fan guard 3A, which is cold in winter, is hard to be bent and is easily cracked. Further, when it is attempted to bend a portion called a weld, it is particularly easily cracked. However, since this fan guard 3A is molded from a synthetic resin as shown in Table 1 and has a very large amount of deflection as shown in FIG. 3, the fan guard may be broken during assembly, or the chassis after assembly may be damaged. The synthetic resin molding used is prevented from cracking.

As described in the claims, the reason for setting the first synthetic resin to 30 to 50% by weight is that 30% by weight is the minimum necessary because if it is less than 30% by weight, it becomes too stiff and brittle. . If it exceeds 50% by weight, it will be too soft and the synthetic resin will be easily bent or deformed.
It should not exceed 50% by weight.

The reason why the second synthetic resin content is 30 to 50% by weight is that if it is less than 30% by weight, it becomes too soft (as opposed to the first synthetic resin) and the synthetic resin is apt to bend or deform. As a result, 30% by weight is a minimum requirement.
If it exceeds 50% by weight, it will become too stiff and brittle,
It should not exceed 50% by weight.

The reason why the content of the third synthetic resin is set to 1 to 20% by weight is that it is used as an additive for softening the synthetic resin.
20% by weight as it becomes too soft when it exceeds
It is desirable to stay within.

Further, the reason why the content of the inorganic filler is 10 to 30% by weight is that if the amount is less than 10% by weight, the rigidity is insufficient, so that 10% by weight or more is necessary. Is too strong, so it is desirable to be within 30% by weight. Further, this inorganic filler uses talc for increasing the rigidity and calcium carbonate for producing the stickiness.

In the present invention, the first synthetic resin and the second synthetic resin are mixed, but if there is a synthetic resin having an elongation rate of 300% or more and a bending elastic modulus of 2000 MPa or more. You may use this. However, since a synthetic resin having such a property has not been found at present, the first synthetic resin and the second synthetic resin are mixed to produce a synthetic resin having such a property.

In this embodiment, an example in which the synthetic resin molded product is used for the exterior body of the air conditioner has been shown, but it may be used for a housing other than the exterior body, for example, an electrical equipment box or the like.

[0026]

According to the invention described in claims 1, 2, 3 and 4, even when a force is applied to the synthetic resin molded product, the amount of deflection is larger than that of the conventional one, so that the synthetic resin molded product is obtained. Can be made difficult to crack.

In particular, according to the third and fourth aspects, although the weld portion formed during the injection molding is particularly liable to be cracked, the synthetic resin molded article is easily deformed due to a large amount of bending, so that it is hard to break. be able to.

Particularly, in the housing according to the fourth aspect, a force that deforms during or after the assembly is easily applied,
Since the amount of deflection is large and it is easily deformed, the housing using this synthetic resin molded product is hard to crack.

[Brief description of the drawings]

FIG. 1 is a perspective view of a housing (air conditioner) using a synthetic resin molded product of the present invention.

FIG. 2 is an explanatory diagram showing a method of assembling the same housing.

FIG. 3 is a diagram showing the relationship between the amount of deflection and the strength of a synthetic resin molded product of the present invention and a conventional synthetic resin molded product.

FIG. 4 is an explanatory diagram showing an experiment for examining the amount of deflection.

[Explanation of symbols]

 2 Indoor unit (housing) 3 Outdoor unit (housing) 3A Fan guard (synthetic resin molded product) 3F Front cover (synthetic resin molded product) 3G Side cover (synthetic resin molded product)

Claims (4)

[Claims] 1. A first synthetic resin having an elongation of 300% or more and a flexural modulus of 1500 to 2000 MPa, and an elongation of 30% or less and a flexural modulus of 2000 to 2
A synthetic resin molded article, which is obtained by mixing a second synthetic resin of 400 MPa, at least one or more third synthetic resin of rubber, elastomer and polyethylene, and an inorganic filler. 2. The first synthetic resin is 30 to 50% by weight,
The second synthetic resin is 30 to 50% by weight, the third synthetic resin is 1 to 20% by weight, and the inorganic filler is 10 to 10% by weight.
30% by weight, and a synthetic resin molded article formed by mixing these synthetic resins and an inorganic filler. 3. The first synthetic resin according to claim 2,
A synthetic resin molded article, characterized by being injection molded from a synthetic resin in which a second synthetic resin, a third synthetic resin and an inorganic filler are mixed. 4. A housing using the synthetic resin molded product according to claim 3.